Brake valve



July 2i?, 1937. c. T. scHMlTT ET AI.

BRAKE VALVE Filed May 27, 1935" 2 Sheets-Sheet 1 FIG.

July 20, 1937 A c. T. scHMlTT ET A1. l 2,087,305

BRAKE VALVE Filed May 27, i955 2 sheets-sheet 2 Patentedl July 2,0, 1937UNITED STATE BRAKE VALVE Charles T. Schmitt, Montclair, and Ernest H.

Brandt, East Orange, N. J.

Application May 27, 1935, seal No. 23,746

4 Claims.

The nature of the invention will more clearly appear from the followingdetailed description of certain preferred embodiments thereof and theappended claims.

In the drawings, Fig. 1 isa side elevationof the assembly of the deviceon an automobile;

Figs. 2 and 3 show in longitudinal cross-section the improved valve innormal and fully.

actuated positions, respectively, thenvalve being reversed as comparedwith the showing in Fig. l;

Figs. 4 and 5 are similar views of a modified form of the valve. x

Referring now to Fig. 1, the valve I is suitably mounted adjacent thecarburetor and manifold 2 of automobile engine 3. The wheel brakes ofautomobile 4 may be operated in anyl suitable manner by depressing afoot pedal extension 5 of a'brake lever 6 fulcrumed on the chassis ofthe :v

automobile at 1. For the sake of clarity and since the details have nobearing on the present invention, the brake-operating mechanism is notshown in the drawings. The lever 6 may be operated also by means of arod 8 actuated by a suitable servo-motor and one end of which isfastened to the lever 6 at 9. Therother end of rod 8 is fastened at I0to a rubber diaphragm I I, the edge of which is clamped between twosections I2 and I3 of the servo-motor casing which"` L, is pivoted at I4on bracket I5 clamped to a steer` ing shaft I6which is operated in theusual manner by the steering wheel I1. Owing to its pivotal mounting,the servo-motor may assume different positions as the brake leverdescends and rises.

y The section I2 of the chamber is open to the atmosphere, but thesection I3 is hermetically sealed by its walls and the rubber diaphragmI I. The chamber I3 is connected through a short piece of rubber tubingI1 toy a copper pipe I8 which in turn is connected with the valve I. I

The carburetorof the automobile is operated in the usual manner by meansof a rod I9 which,

22 which may be longicylindrical 4plunger 21 forming part of the valvemechanism, may be operated. I

A port 28 (Fig. 2) in valve casing 29 is connected with the'enginemanifold-and the copper tubek I8 is connected with port 36 in thecasing. When, during the operation of thevalve to be presentlydescribed, suction is applied from the ,manifold,' air "will beexhausted from the servomotor chamber I3 through the rubber tubing I1,pipe I8, port 36, the casing 29 of valve I, and the port 28. This willmove the diaphragm I I down, whereby through the rod 8 thebrake-actuating lever will `be rotated in a clockwise direction to applythe wheel brakes. When atmospheric pressure is reestablished within thevalve casing 29 and the chamber I3 connected therewith, the

diaphragm Il and brake lever 6 will be moved/ back towards the positionshown in Fig. 1. by means of the usual spring mechanism (not shown) Theoperation of the valve I is as follows: The plunger 21 projects axiallythrough casing 29 and is longitudinally slidable therein. The hollowplunger 21 is provided near its operating knob 26 with ports 3I whichare always open to the atmosphere, and its other end carries a cup 32within which is seated one end of a coiled spring 33. The other end ofthe coiled spring 33 presses against a cap 34 mounted on a recessedshoulder `35 of casing 29, whereby spring 33 will always tend to keepthe plunger 21 in the position shown in Fig. 2. The bearing surfaces -onwhich the 4plunger 21,may slide are constituted \,by the shoulder 35, awall 36 within the casing 29,.,and a sleeve 31, 38. The sleeve 31, 38 isslidable"w\ith respect to the casing 29 and the plunger 21, butisnormally held in the position shown in Fig. 2 by means of a coiledspring 39, one end of which rests in a recess of wall 36 and the otherend of which 'engages a flange 40 on sleeve sectionA 31'. plunger 21 anda 42 of the valve casing at 43 to the casingpqrtion travel against thetension of the width of `iiange 4I on the As will b e ob`l served fromFigs. 2 and 3,` the distance which 'constituted by an annular vcounter-clockwise 41 on sleeve section 38 and a ring 48.screwed onsleeve 38." The compartment 44 is open to the atmosphere as indicated at49. 'I'he compartment 45 communicates through port 38 and the tubing I8,I1 with the servo-motor-compartment I3. A third. compartment withincasing 29 is passage 5 around plunger 21 and between wall 36 andtheshoulder 35 of casing 29. The port 28 opens into the an; nularcompartment 50.

The inside of the plunger 21 three sections or compartments by means ofa hollow cylinder 5| having anges 52 and 53 at its ends which engage theinside of plunger 21. The cylinder 5| maybe integral with plunger 21onmay be a separate piece frictionally held in the plunger. The iirstone of these chambers is 54 which, as above stated, communicates withthe atmosphere through ports 3|. It is provided also with ports 55 whichcommunicate with chamber 45 through holes 31 bored in between shoulders40 and 41, said holes communicating with'a channel 38( cut in the innerface of the sleeve. The` second compartment is an annular chamber orpassageway 56 between the outside surface of cylinder/ 5| and the insidesurface of plunger 21. 'I'his compartment has a row'of ports near eachend 51 and 58, respectively. 'I'he third compartment is 59. It is opento the atmosphere through the end of plunger 21 and communicates withcompartment 54 through the cylinder 5I.

With the device in the position shown vin Fig. 2, when the engine isworking, suction will be applied from the manifold through port 28 andchamber will be evacuated. All the other chambers and compartments ofvalve I and is divided into vtherefore the vacuum compartment I3 of theand permits it to rotate in.a direction ,under the action of the usualspring 2|a actuating the linkage 20, the rod I9 will be longitudinallymoved .from left I3 of the servo-motor through the tubing chamber 45,ports 51l passageway 56, ports 58,

down as above described and apply the brakes. As the pressure in chamber45 is reduced the diaphragm 46 of the valve is moved towards the sleeve31, 38"

5s immediately' l1, 18, port'30, o

aosaaos fore the servo-motor chamberN I3, from chamber 56. The furtherexhaustion of air from cham-y bers 45 and I3 is stopped rbut the brakesremain applied.

When the operator again depresses pedal 2| suilciently to remove finger25 from the knob 26, spring 33 will drive plunger 21 from right to left.First,`ports 55 will clear the shoulder on sleeve 431 and connectchamber 45 through the apertures 31 with compartment 54 in the plunger21., Air will rush into'chamber 45 and through port 30 into vacuumchamber I3, permitting the restoration of brake lever 6 to normal underthe control of the usual spring (not f' shown).. Furthermore, as airpressure is increased within the chamber 45, the spring 39 will push thesleeve 31, 38 towards the position shown 4in Fig. 2. It will be notedthat duringthe return of sleeve 31 to normal it maintained the ports 51of chamber 56 closed, whereby this chamber will remain evacuated,although in the normal position of the valve its ports 58 are not incommunication closed by the wall 36.

l Owing to the fact that chambers 50 and 56 are, during the operation ofthe. engine, constantly under -low pressure, the-instant when upon theactuation of plunger 21 the ports 51 clear sleeve 31, the air inchambers 45 and I3 will rush into the low pressure chambers 56 and 50,the communication between chamber 45 and accelerator pedal applicationof the brakes will then be gradually 'increased as' air is sucked out ofchambers 45 and I3. This arrangement guards against ranged Vto r applybraking capacity. The additional 5% may be applied, if necessary, by thedriver bearing down on the brake pedal 5. Since in the actuated posltiongof the plunger the .ports 55' are just past the left edge of sleeve31, the instant pedal 2| is Ydepressed these ports will clear the sleeve31 and permit air to rush into chambers 45 `and I3, relieving pressureon the brakes.

' As indicated in the drawings, the ports 55, 51 and 58 are withinradial grooves cut in the outside surface of plunger 21, whereby all theports of a row communicate with one another. 'Ihis will guard againstfailure of operation should one ports become stopped up and also againsta the binding of plunger 21 on its bearing surfaces, since the suctionapplied to the plunger Vsurfaces by the constant maintenance ofatmospheric pressure in compartments 54 and 59 of the plunger andin theenclosure 34 around the end of plunger 21.

with the chamber 50, but are approximately 95% of the total hermeticSeaLsuicient air would seep intochamber 45 to permit spring 39to'restore the diaphragm assembly to'normal,and, of course,atmos phericpressure will be reestablished in chambers 45 and |13, whereby thebrakes will go off. To guard against this, in the arrangement shown inFigs. 4 and 5, chamber 50A is made somewhat smaller so that in theactuated position of plung er 21A (Fig. 5), the ports'58A clear thischamber and are` closed by shoulder A of casing 29A. Also, even in thefully actuated position of the plunger, ports 51A remain incommunication with chamber 45A. Should, therefore, the driver stall hismotor and should air 28A into ,chamber 50A, this air cannot escape intochamber 56A and thense into chambers I15A and vI3, whereby .the brakeswill remain applied, whether or not the engine is running. The releaseof the brakes can be effected only by `relieving foot pressure on pedal2| and permitting plunger 21A to return to normal under the action ofspring 33A.

In this structure also the end compartmentaction of the spring 33A toreturn the plunger -sleeves 38 and 35, whereby to normal-when desired.The restoring spring may, therefore, be light, insuring 'ease ofoperation of the plunger. Besides, in this as well as the embodiment.disclosed in Figs. 2 and 3, air

will penetrate between the outside surface of the plunger and thebearing surfaces constituted by plunger is insured without the use ofanyadditional lubricant. If the ends of the plunger were not thusair-lubricated, the lmetallic surfaces would bind, since any lubricantconducted thereto would be blown'out during the operation of the valve.

What we claim is:

1. In a valve for controlling the application o f brakes in anautomobile, a casing enclosing three chambers, a flexible diaphragmdividing one of said chambers into two compartments, the first one ofsaid compartments and the third chamber being permanently open to theatmosphere, 'a cylindrical plunger projecting throughout said casing,partitions-in said plunger dividing it into three sections, the rstsection having ports communicating with the atmosphere and the thirdsection, and ports normally communicating with the second compartmentthe second section having two sets of ports, one adapted to communicatewith the second compartment of the y with'the second chamber, aspring-pressed sleeve within said rst chamber surrounding said plungerand projecting through said diaphragm, said sleeve having openingscommunicating with the second set of ports in the rst section of theplunger and with the second compartment in the first chamber,A aconnection from the manifold ofthe'automobile engine to the secondchamber, and

rush in through port free sliding of thev of the first chamber,

first'chamber and the other l a spring-pressed sleeve plunger and thewall of said third chamber, partitions in said plunger dividing it intothree sections, the first section having ports communieating with ,theatmosphere and the third section, and ports, normally communicating withthe second compartment of the rst chamber, whereby atmospheric pressurewill be maintained in side and outside of the iirst and third .sectionsof the plunger, the second section having two sets .of ports, oneadapted `to communicate with the second compartment of the rst chamberand the other with the second chamber, a spring-pressed sleeve withinsaid first chamber surrounding said plunger and projecting through saiddiaphragm, said sleeve having openings normally communicating with thesecond set of ports in the rst section of the plunger and with thesecond compartment in the rst chambe ,a connection from the manifold ofthe automobile engine to the secondchamber, a servo-motor connected.with the second compartment of the rst chamber, and means for movingsaid plunger with respect to said casing and sleeve.

3. In a valve for controlling the application of brakes inan automobile,a casing enclosing two chambers, a connection between the enginemanifold and the lirst chamber and a connection between the secondchamber and the brakes, a hollow plunger traversing said casing and opento the atmosphere through a substantial portion of its length, means formoving the plunger in one direction and a spring tending to move it in,

'iirst the rst port communicates with the first chamber and then thesecond .port with the second chamber, means responsive to air pressurein the second chamber for closing s aid second port, and a exible wallfor said second to the last mentioned means and having one sideexposed-to atmpheric pressure.

4. In a valve for controlling the application of brakesiin anautomobile, a. casing enclosing two chambers, a connection betweentheengine mani-l fold and the rst chamber and, a connection' between thesecond chamber andthe brakes, a hollow plunger traversing said casing,means for moving the plunger in one direction and a spring tending tomove it in the opposite direction, a closed passageway through thecentral portion of the plunger and having two ports, the end portions ofthe plunger being open to the atmosphere, said ports being so spacedthat during the moving of the plunger in one direction rst the Vrst portcommunicates with the first chamber and then Athe second port with thesecond chamber, in the second chamber surrounding said plunger, and aflexible wall for said second chamber fastened to said sleeve.

CHARLES T. SCHBMTI.

ERNEST BRANDT.

chamber attached

